1966-1986
made about 1972
Made in 1975.
Made in 1967.Second year of production.
No such sn in the Diamondback series
You must call Colt to find out.
what is the manufacturing date fo a colt diamondback serial number O72239
You will have to call Colt.
Go to proofhouse.com and click on diamondback.
You will have to call Colt. Published sn data does not show any Diamondback with a sn starting with a P
Go to : www.proofhouse.com
That was 1971.
You can find out at Proofhouse.com in the Colt tables.